2 files changed, 2 insertions, 1 deletions
diff --git a/deno_typescript/lib.deno_core.d.ts b/deno_typescript/lib.deno_core.d.ts
index c3a20eb08..549665543 100644
--- a/deno_typescript/lib.deno_core.d.ts
+++ b/deno_typescript/lib.deno_core.d.ts
@@ -21,7 +21,7 @@ interface EvalErrorInfo {
 }
 
 declare interface DenoCore {
-  print(s: string, isErr?: boolean);
+  print(s: string, isErr?: boolean): void;
   dispatch(
     opId: number,
     control: Uint8Array,
diff --git a/deno_typescript/lib.rs b/deno_typescript/lib.rs
index 56072ebdc..e53a4243d 100644
--- a/deno_typescript/lib.rs
+++ b/deno_typescript/lib.rs
@@ -127,6 +127,7 @@ pub fn compile_bundle(
 
   let config_json = serde_json::json!({
     "compilerOptions": {
+      "strict": true,
       "declaration": true,
       "lib": ["esnext"],
       "module": "amd",